ANSI / ASME B16.5 Class 900 Weld Neck Flange Dimensions
| Nominal Pipe Size | Outside Diameter (O) | Thickness (T) | Raised Face Diameter (R) | Length Thru Hub (Y) | Hub Diameter (X) | Bore (B) | Approximate Weight (lbs) | Bolt Circle (C) | Number of Holes | Diameter of Holes |
|---|---|---|---|---|---|---|---|---|---|---|
| 1/2 | 4.75 | 0.88 | 1.38 | 2.38 | 1.50 | Specified by purchaser | 5 | 3.25 | 4 | 0.88 |
| 3/4 | 5.13 | 1.00 | 1.69 | 2.75 | 1.75 | Specified by purchaser | 6 | 3.50 | 4 | 0.88 |
| 1 | 5.88 | 1.13 | 2.00 | 2.88 | 2.06 | Specified by purchaser | 9 | 4.00 | 4 | 1.00 |
| 1 1/4 | 6.25 | 1.13 | 2.50 | 2.88 | 2.50 | Specified by purchaser | 10 | 4.38 | 4 | 1.00 |
| 1 1/2 | 7.00 | 1.25 | 2.88 | 3.25 | 2.75 | Specified by purchaser | 13 | 4.88 | 4 | 1.13 |
| 2 | 8.50 | 1.50 | 3.63 | 4.00 | 4.13 | Specified by purchaser | 25 | 6.50 | 8 | 1.00 |
| 2 1/2 | 9.63 | 1.63 | 4.13 | 4.06 | 4.88 | Specified by purchaser | 36 | 7.50 | 8 | 1.13 |
| 3 | 9.50 | 1.50 | 5.00 | 4.00 | 5.00 | Specified by purchaser | 31 | 7.50 | 8 | 1.00 |
| 4 | 11.50 | 1.75 | 6.19 | 4.50 | 6.25 | Specified by purchaser | 53 | 9.25 | 8 | 1.25 |
| 5 | 13.75 | 2.00 | 7.31 | 5.00 | 7.50 | Specified by purchaser | 86 | 11.00 | 8 | 1.38 |
| 6 | 15.00 | 2.19 | 8.50 | 5.50 | 9.25 | Specified by purchaser | 110 | 12.50 | 12 | 1.25 |
| 8 | 18.50 | 2.50 | 10.63 | 6.38 | 11.75 | Specified by purchaser | 175 | 15.50 | 12 | 1.50 |
| 10 | 21.50 | 2.75 | 12.75 | 7.25 | 14.50 | Specified by purchaser | 260 | 18.50 | 16 | 1.50 |
| 12 | 24.00 | 3.13 | 15.00 | 7.88 | 16.50 | Specified by purchaser | 325 | 21.00 | 20 | 1.50 |
| 14 | 25.25 | 3.38 | 16.25 | 8.38 | 17.75 | Specified by purchaser | 400 | 22.00 | 20 | 1.63 |
| 16 | 27.75 | 3.50 | 18.50 | 8.50 | 20.00 | Specified by purchaser | 495 | 24.25 | 20 | 1.75 |
| 18 | 31.00 | 4.00 | 21.00 | 9.00 | 22.25 | Specified by purchaser | 680 | 27.00 | 20 | 2.00 |
| 20 | 33.75 | 4.25 | 23.00 | 9.75 | 24.50 | Specified by purchaser | 830 | 29.50 | 20 | 2.13 |
| 24 | 41.00 | 5.50 | 27.25 | 11.50 | 29.50 | Specified by purchaser | 1500 | 35.50 | 20 | 2.63 |
*Use 25.4 as a factor to convert into mm.